public member function
<iterator>
reverse_iterator& operator--();
reverse_iterator operator--(int);
Decrease iterator position
Decreases the reverse_iterator by one position.
Internally, the pre-decrement version (1) increments the base iterator kept by the object (as if applying operator++ to it).
The post-decrement version (2) is implemented with a behavior equivalent to:
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reverse_iterator operator--(int) {
reverse_iterator temp = *this;
--(*this);
return temp;
}
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Parameters
none (the second version overloads the post-decrement operator).
Return value
The pre-decrement version (1) returns *this.
The post-decrement version (2) returns the value *this had before the call.
Example
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// reverse_iterator::operator-- example
#include <iostream> // std::cout
#include <iterator> // std::reverse_iterator
#include <vector> // std::vector
int main () {
std::vector<int> myvector;
for (int i=0; i<10; i++) myvector.push_back(i);
typedef std::vector<int>::iterator iter_type;
std::reverse_iterator<iter_type> rev_begin (myvector.end());
std::reverse_iterator<iter_type> rev_end (myvector.begin());
std::reverse_iterator<iter_type> rev_iterator = rev_begin;
while ( rev_iterator != rev_end )
std::cout << *rev_iterator++ << ' ';
std::cout << '\n';
while ( rev_iterator != rev_begin )
std::cout << *(--rev_iterator) << ' ';
std::cout << '\n';
return 0;
}
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Output:
9 8 7 6 5 4 3 2 1 0
0 1 2 3 4 5 6 7 8 9
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Data races
Modifies the object.
The iterator returned can be used to access or modify pointed elements.
Exception safety
Provides the same level of guarantee as increasing (and copying, for (2)) the base iterator.